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Methicillin-resistant Staphylococcus aure s (MRSA) has become a more frequent pathogen within health care facilities and the community. MRSA causes infections that can’t be treated with β-lactamantibiotics. To prevent the spread of MRSA, patients and medical personnel undergo screening-tests. In the screening-tests PCR-analysis of mecA, nuc and/or Sa442 is included. MecA is located at Staphylococcal Chromosomal Cassette mec (SCCmec) and is a marker for MRSA, whereas nuc and Sa442 state regular S. Aureus infections. PCR-positive isolates are grown on agar plates after enrichment in selective broth. Colonies of S. aureus are tested for cefoxitin susceptibility to which MRSA is resistant. PCR-analysis of mecA is the reference method that is being used today when MRSA is being diagnosed. During the last decade cefoxitin-resistant strains that lack mecA in the PCR has been reported. In 2011 a new variant of SCCmec and a new variant of mecA, mecALGA251 was reported. In this study a new real-time-PCR has been developed in order to identify mecALGA251. The new PCR protocol was being used to examine 43 clinical isolates, four cefoxitin-susceptible S. aureus from the routine and three reference strains were examined. The clinical isolates had been collected during the period 2004-2011 and were cefoxitin-resistant but lacked mecA. In total of 40 of the 43 cefoxitin-resistant was PCR positive for mecALGA251. Susceptibility testing with disk diffusion and E-test for cefoxitin, oxacillin, cefuroxime and cefotaxime showed that this type of MRSA can’t be distinguished from regular MRSA. The results showed that cefoxitin-resistant
S. aureus isolates carrying mecALGA251 exist among patients in Skåne County. One cefoxitin-resistant S. aureus isolate lacked both classic mecA and mecALGA251, which indicates that other mechanisms may exist, however these results has not been further analysed in this study.